On May 20, 2014, Dodge finally unveiled the 2015 Dodge Challenger SRT cars, one with the 392, the other with the 707-horsepower, supercharged 6.2 Hemi. Either V-8 engine could be mated with a six-speed manual transmission or a beefy new TorqueFlite eight-speed automatic.

On July 1, 2014, the 100th anniversary of the founding of Dodge Brothers, the horsepower and torque ratings of the new Hemi engine were made official: 707 hp and 650 lb-ft of torque. The official NHRA quarter-mile times were 11.2 @ 125 mph on stock tires, and 10.8 @ 126 mph on drag slicks.

The 392 engine has been upgraded from 470 to 485 horsepower, with torque climbing from 470 to 475 lb-ft. Fuel economy is 14/23 for the manual, 15/25 for the automatic, up 1 mpg city and 2 mpg highway over the 2014 models with their five-speed automatics (unchanged with the automatic).

According to reliable source oh2o, Dodge made 7,168 Challenger Hellcats for the 2015 model year, and 3,889 for the 2016 model year — just through February 29, 2016. The plan is to have 20,000 total for 2015-16 (with around 2,500 Chargers already made for the two years).

The supercharged engine uses a forged-steel crankshaft with induction-hardened bearing surfaces, which can withstand firing pressures of 110 bar (1,595 psi) – the equivalent of five family sedans standing on each piston, every two revolutions. Its unique crank damper has been tested to 13,000 rpm. Sodium-cooled exhaust valves use hollow-stem construction and steel-alloy heads that stand up to temperatures as high as 1,472° Fahrenheit (800° Celsius). Cam profiles afford 14.25-mm inlet and 14.0 mm of exhaust lift.

Hellcat-equipped cars come with two key fobs, red and black; the red key fob unlocks the full horsepower and torque of the Challenger SRT Hellcat engine, while the black fob limits engine output to 500 horsepower (as predicted by Allpar a month before the announcement).

Valet Mode, standard with both Challenger SRT engines, makes the following changes:

Power output is cut, and engine speed is limited to 4,000 rpm

Access to first gear is locked out, and the transmission upshifts early; it treats the “manual override” position as “Drive”

Paddle shifters are disabled

Drive Mode is set to “Street” with no override

Electronic Stability Control (ESC) is enabled to Full-on

Launch Control is disabled

The driver can activate and deactivate Valet Mode with a four-digit PIN.

2017 updates

Every Challenger gets new Destroyer Gray and Octane Red paints, and Apple CarPlay/Android Auto support. The Hellcat cars get new 20 x 9.5 inch “lightweight 5Deep aluminum” wheels with five spokes, finished in low-gloss black; they save four pounds per wheel. There is also new interior and exterior badging, and an LED-lit steering wheel (red on Hellcat, white on 392).

The Drive Mode feature is controlled through the Uconnect system and may be accessed by pushing the SRT button on the instrument panel, from the “SRT & Apps” menu on the touch screen, or from the Performance Pages.

Standard wheels on the Challenger SRT with the Hellcat engine are new “Slingshot” split-seven spoke 20 x 9.5-inch, lightweight forged-aluminum wheels with a matte black finish (also used on the SRT 392 as part of the SRT Track Pack). Available on the Challenger SRT Hellcat are 20 x 9.5-inch, lightweight forged-aluminum wheels with a Brass Monkey/dark bronze finish.

The Hellcat had the largest front-brake package ever used in an SRT vehicle, with 390-mm (15.4-inch) Brembo two-piece rotors with six-piston calipers, also available on the 392 as part of the SRT Track Pack. New anti-lock braking system (ABS), ESC, and traction control systems were configurable for specific tire and powertrain configurations.

2015 Changes

Tiana Seraphine wrote:

2015 and 2016 SRT392 specs are somewhat different, with the 2016 cars getting six-piston front brakes, 9.5” wheels, 275/40R20 tires (both the same as the Hellcat), Hyper Black wheel paint for the 392 only, with flat black and Brass Monkey wheels only available on Hellcat. The rear spoiler was color-matched to the car for 392, while Hellcat spoilers were black only.

In general terms, the Scat Pack is basically an R/T with an upgraded engine (four-piston front brakes, but they are Brembos on the Scat Pack), and the Hellcat is in general terms an SRT 392 with an upgraded engine and related systems, particularly cooling (the 392 and Hellcat share the wheels, brakes, and adjustable suspension). This is important given that 392 production numbers are much lower than both the Scat Packs and Hellcats, which should make them more rare in the future.

Both the 2016 Charger SRT cars — 392 and Hellcat — also got standard Laguna leather interiors (with a price boost on Hellcats), large touch-screen navigation systems, HD radio, and five years of satellite TravelLink and traffic. Plum Crazy, TorRed, and B5 Blue were limited-edition paints, with GoMango added in March 2016. There was a hefty price boost with the new features.

Exterior design

A larger, power-bulge aluminum hood had a “cold-air” intake; the Hellcat hood also had twin air extractors to remove heat and cut air turbulence in the engine bay, in body color (optionally in satin black). Both Challenger SRTs have aluminum hoods to reduce weight. The Challenger SRT Hellcat also has an Air Catcher inlet port, which rams air directly into the engine air box through the driver-side parking lamp. All the cooling helps the engine stay at peak power through hot days.

Integrated projector fog lamps on the Challenger 392 SRT were pushed to the lower corners, and a duck-bill fascia splitter improved aerodynamics. The Hellcat has a larger front splitter for optimal downforce, and “SUPERCHARGED” fender badges which were quickly replaced by cat logos. Black sills were tuned in the wind tunnel. A taller rear spoiler on the Hellcat wore a raised SRT logo.

Many of the most memorable paint colors in automotive history have been found on the Challenger. Both SRT Challengers will be available in B5 Blue, Billet Silver Metallic, Bright White, Granite Crystal Metallic Pearl, Ivory White Tri-Coat Pearl, Jazz Blue Pearl, Phantom Black Tri-Coat Pearl, Pitch Black, Redline Tri-Coat Pearl, Sublime Metallic Pearl, and TorRed. Twin, full-body stripes are available in black gloss and silver gloss on the SRT 392.

The instrument panel has a stamped aluminum bezel; a 7-inch configurable display is flanked by analog gauges, drawn from the “tic-toc-tach” 1971 designs. With the Hellcat, the gauges and graphics are both finished in a dark Radar Red tone. New for 2015, drivers can select a background for the 8.4 inch touch-screen.

The aluminum trim gets one of two finishes, “Hectic Mesh” for the Challenger 392 SRT and “Dark Engine Turn” for the Challenger SRT Hellcat. The center console houses redundant button and knob controls for the audio and climate system; a new media hub with an SD card slot, USB outlet, and audio jack is inside the center console’s armrest.

The TorqueFlite eight-speed automatic transmission has a new electronic shifter with a driver-oriented T-handle for intuitive gear selection, and an Auto Stick selector gate. The track-proven Tremec TR6060 six-speed manual transmission has a throwback ball shifter.

A redesigned SRT-branded heated steering wheel has a flat bottom and available paddle shifters (with automatic transmission). This new tilt-telescoping steering wheel also has a 360-degree heat element. Seat comfort has also been improved, and ventilated/heated front seats are standard. The passenger seat has an easy exit/entry system for rear seat access. Seats are covered in Nappa leather/Alcantara material with embroidered SRT logo, with Laguna leather, either sepia or black with embossed SRT logos, available as part of an equipment package.

Production is scheduled to begin in the third quarter of 2014, with ordering to begin in the summer.

Drivetrain upgrades

A new M-gate shifter and steering-wheel-mounted paddles better connect driver and transmission; there are nearly 200 possible drive-mode combinations from the distinct settings (default, sport, track, valet, and custom). Launch Control is standard, and enhanced by stiffer, asymmetric half-shafts that minimize “power hop” under hard acceleration, and a new driveshaft with high-strength CV joints; both driveshafts and half-shafts have new lubricants for higher-speed operation.

Transmission

1

2

3

4

5

6

7

8

R

Final

OTGR

Auto (392)

4.71

3.14

2.10

1.67

1.29

1.00

0.84

0.67

3.30

3.09

2.07

Auto (Hellcat)

4.71

3.14

2.10

1.67

1.29

1.00

0.84

0.67

3.30

2.62

1.76

Manual (392)

2.97

2.10

1.46

1.00

0.74

0.50

2.90

3.90

1.95

Manual (Hellcat)

2.26

1.58

1.19

1.00

0.77

0.63

2.90

3.70

2.33

The Tremec TR-6060 manual transmission has a 240 mm twin-disc ZF-Sachs clutch with the 392, a 258 mm version of the same clutch with the Hellcat. Both have a triple cone (1, 2)/double cone (3-6) synchronizer design, with 1-4 skip-shift and reverse-inhibit solenoids and a 5:1 remote shifter. The differential is asymmetric-limited slip on all Challenger SRTs.

A new, 230-mm rear axle was needed for the higher torque; the new axle is more efficient, with a lightweight aluminum housing, cooling fins, high efficiency bearings, and low-viscosity fluid. Durability measures include welded ring gears, shot-peened gear material, hardened shims, four-opinion differential, and four-point mounting.

An asymmetric limited-slip differential allows for unique bias-ratio tuning for on- and off-throttle behavior. This enhances grip, stability, and steering response, for hard acceleration on corner exits. When trail-braking, the differential further tightens to stabilize the car and prevent oversteer.

SRT powertrain chief Chris Cowland wrote that they specified “the ability to complete 20 minutes of full-speed track driving in extreme ambient temperatures without the need for cooling-system-driven derate. This places significant burden on the cooling capacity of the vehicle.”

Supercharger and engine details

Exhaust

The exhaust note was custom-engineered using an electronically controlled exhaust valve; the first time a 2015 Dodge Challenger SRT Hellcat was fired up on the assembly line in Ontario, workers came running to investigate. The 2.75-inch, straight-through, twin-exhaust system includes durable, double-walled exhaust manifolds and ceramic catalysts capable of withstanding temperatures up to 1,922° Fahrenheit (1,050° Celsius).

Performance Pages

Real-time performance information is shown on the gauge or center screen, and can be saved to a USB or uploaded to the Mopar’s Owner Connect page. Drivers can launch the app by voice; when they push the Timer button on the touchscreen, they’re connected to the “reaction time” feature, which gives the driver a 2.5-second countdown. From there, they can access screens with:

Timers: Top speed, 0-60 mph acceleration, 0-100 mph acceleration, one-eighth mile and one-quarter mile times and distances, reaction time (against a light), and lap time. The system can also show braking distance. All timers can be shown with current, best, or last.

G-Force: Real-time lateral G-force measures left and right (turning) force, while longitudinal G-force shows the acceleration and braking force; peak shows the maximum g-forces that have been achieved.

The rumors

Allpar first reported on a supercharged 6.2 Hemi coming down the line on June 18, 2012. At that time our sources were predicting 700 horsepower, and based on experience with such predictions, we assumed it would end up at around 580-600. Eventually, as more news came in, we bumped that estimate up to 640-680 horsepower, but since it will be paired with an eight-speed automatic (in Dodge Charger and as an option in Dodge Challenger SRT), we also assumed torque would be limited to 640 lb-ft of torque.

Allpar’s predictions of the Hellcat logo and dual power levels have both been shown to be mainly correct. Thank you, oh2o and other sources!